ILC's High-Energy Collisions Require Accurate Energy Measurements

July 3, 2007
ILC's High-Energy Collisions Require Accurate Energy Measurements
University of California, Berkeley, student Erik Petigura (left) and Alexey Lyapin of University College London stand by components of the energy spectrometer in End Station A.

The International Linear Collider (ILC) collaboration proposes to crash electron and positron beams together with a total energy of 500 GeV (billion electron volts). The actual energy of each beam will vary slightly from one bunch of particles to the next, so just before the collision point, energy spectrometers will measure each bunch's exact energy.

"We need to be able to measure the beam energy with an accuracy of one part in 10,000 to establish the masses of the new particles we'll hopefully see," said Yury Kolomensky, associate professor of physics at the University of California-Berkeley.

Kolomensky and his collaborators (from SLAC, the University of California, Berkeley, and the University of Notre Dame in the U.S.; University College London, Royal Holloway College, and Cambridge University in the U.K.; DESY in Germany; and Dubna in Russia) have installed their prototype energy spectrometer on the beam line in End Station A. For most of July, a test beam of electrons will whiz down the beam line, letting Kolomensky and others test equipment under ILC-like conditions. The energy of the test beam is about ten times less than that of an ILC beam, but has the same bunch length and charge.

Existing spectrometers can't provide the required accuracy for a single bunch at a time. The prototype starts where most energy spectrometers do, with a set of magnets that deflect the beam. Beam position monitors, provided by SLAC and a group from University College London, measure the amount of deflection. The higher the beam's energy, the less the beam gets deflected. In End Station A, four magnets bend the beam about 5 millimeters horizontally over the course of the 20-meter-long energy spectrometer set-up.

In addition, the prototype has a way to very precisely and very accurately measure the magnetic field over the entire spectrometer during each pulse of the beam. 'Precisely' is like throwing darts that all land very close to one another; 'accurately' is all those darts hitting the bull's-eye. Collaborators from DESY and Dubna worked with the Magnetic Measurement Group at SLAC this past fall and winter to determine the magnetic fields at all positions along the beam trajectory through the spectrometer magnets.

After testing the components in March, researchers are now ready to run. "The goal is to have a demonstration of the technology that will ultimately go into the ILC design," Kolomensky said.

Source: by Heather Rock Woods, SLAC Today

Explore further: Catching proteins in the act

Related Stories

Catching proteins in the act

August 23, 2016

Some of the fastest processes in our body run their course in proteins activated by light. The protein rhodopsin sees to it that our eyes can rapidly take in their ever-changing surroundings. Free-electron X-ray lasers such ...

NIST's compact gyroscope may turn heads

August 23, 2016

Shrink rays may exist only in science fiction, but similar effects are at work in the real world at the National Institute of Standards and Technology (NIST).

Physicists propose method for braiding light

August 22, 2016

(Phys.org)—Physicists have proposed a way to braid three beams of light by guiding the beams along swirling, vortex-shaped defects in the optical medium through which the beams travel. The braided light would have an unusual ...

Light and matter merge in quantum coupling

August 22, 2016

Where light and matter intersect, the world illuminates. Where light and matter interact so strongly that they become one, they illuminate a world of new physics, according to Rice University scientists.

Recommended for you

Engineers discover a high-speed nano-avalanche

August 24, 2016

Charles McLaren, a doctoral student in materials science and engineering at Lehigh University, arrived last fall for his semester of research at the University of Marburg in Germany with his language skills significantly ...

Understanding nature's patterns with plasmas

August 23, 2016

Patterns abound in nature, from zebra stripes and leopard spots to honeycombs and bands of clouds. Somehow, these patterns form and organize all by themselves. To better understand how, researchers have now created a new ...

Stretchy supercapacitors power wearable electronics

August 23, 2016

A future of soft robots that wash your dishes or smart T-shirts that power your cell phone may depend on the development of stretchy power sources. But traditional batteries are thick and rigid—not ideal properties for ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.